I've just recently rewound a villiers coil after stripping back the original windings. Hopefully, with no shellac to go bad and corrode the copper, it should last for longer than the original.
Instead of using silk and shellac, I went with Kapton (polyimide) tape to hold the coil together and insulate the layers of the secondary winding. This is the stuff NASA use on spacecraft (it gives the gold foil the gold colour) and is extremely heat resistant and insulating. It should last much longer than the old version.
The coil was wrapped in brown paper when it was finished, and given four coats of polyurethane varnish, and epoxy sealed around all the holes and gaps to prevent water getting in if the outboard ends up overboard.
I believe this was the very early villiers type coil - the flywheel had four holes in it. It was on a model 102 with a clutch which strangely had no serial number, yet had some plastic fittings. My guess is mid fifties.
The rev counter was a fairly simple arduino program with a LCD and a small roller switch that went over a bump glued to the chuck.
Code is here if anyone fancies building their own. I'm not a coder so this is pretty messy and borrows from a bunch of different places. The arduino was about £5.00 and the LCD was about £4.50 off the internet.
Code: Select all
#include <Wire.h>
#include <LiquidCrystal_I2C.h> // Using version 1.2.1
// The LCD constructor - address shown is 0x27 - may or may not be correct for yours
// Also based on YWRobot LCM1602 IIC V1
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);
// constants won't change. They're used here to set pin numbers:
const int buttonPin = 2; // the number of the pushbutton pin
// Variables will change:
int buttonState; // the current reading from the input pin
int lastButtonState = LOW; // the previous reading from the input pin
long count = 0;
// the following variables are unsigned longs because the time, measured in
// milliseconds, will quickly become a bigger number than can be stored in an int.
unsigned long lastDebounceTime = 0; // the last time the output pin was toggled
unsigned long debounceDelay = 10; // the debounce time; increase if the output flickers
void setup()
{
Serial.begin(9600);
pinMode(buttonPin, INPUT);
lcd.begin(16, 2); // sixteen characters across - 2 lines
lcd.backlight();
// first character - 1st line
lcd.setCursor(0, 0);
lcd.print("Rev Counter");
// 8th character - 2nd line
lcd.setCursor(0, 1);
lcd.print("Count =");
}
void loop() {
// read the state of the switch into a local variable:
int reading = digitalRead(buttonPin);
// check to see if you just pressed the button
// (i.e. the input went from LOW to HIGH), and you've waited long enough
// since the last press to ignore any noise:
// If the switch changed, due to noise or pressing:
if (reading != lastButtonState) {
// reset the debouncing timer
lastDebounceTime = millis();
}
if ((millis() - lastDebounceTime) > debounceDelay)
{
// whatever the reading is at, it's been there for longer than the debounce
// delay, so take it as the actual current state:
// if the button state has changed:
if (reading != buttonState) {
buttonState = reading;
// only toggle the LED if the new button state is HIGH
if (buttonState == HIGH) {
count++;
}
}
}
lcd.setCursor(8, 1);
lcd.print(count);
Serial.println(buttonState);
delay (20);
// save the reading. Next time through the loop, it'll be the lastButtonState:
lastButtonState = reading;
}
The wire runs from the spool between two bits of wood screwed together with felt sandwiched between to keep the wire in tension but not prevent it from sliding. This meant I could stop and start the lathe without worrying about having to hold the wire and maybe snap it.
The notes I took to make sure I rebuilt it the same as it was before.
I rewound the coil with 0.8mm wire and 0.15mm wire for primary and secondary windings respectively. I didn't wind to the original numbers of windings, instead winding three layers of primary (same as the original) and then as many layers as I could get from a 50g spool of secondary. I calculated (from 180 turns on the primary) that I needed 18,000 secondary windings, but I ended up with about half of that before I ran out of space and wire. Nevertheless, the coil produces a spark and the outboard runs again.
The total cost of the materials to rewind the coil was £18 for the Kapton tape and wire.